A use for integer quotients
Marcin 'Qrczak' Kowalczyk
qrczak at knm.org.pl
Mon Jul 23 17:48:57 EDT 2001
Mon, 23 Jul 2001 22:34:07 +0100, Stephen Horne <steve at lurking.demon.co.uk> pisze:
>>No no no. '3.' i.e. a floating point number with that value could be
>>anything in that range. '3' means exactly the integer 3, no approximation
>>at all.
>
> A mathematician is free to use '3' to represent a real - the fact that
> it is real is implicit in the context. Compilers and interpeters
> aren't able to determine that, so integers and floats have different
> notations even when the represent equivalent values.
When we are considering exactness, value is not the only thing that
matters. 3 and 3. have the same value and the primary difference is that
3 is integer, discrete, exact, where 3. is real, analog, continuous,
fuzzy.
> We can't exactly match mathematics here, but we don't have to go so
> far as having different symbols for integer and float division -
> mathematics uses the same set of symbols for both operations allowing
> the context choose the operator.
I've never seen / as integer division in mathematics. The only notation
I know is
| a |
| - |
|_ b _|
i.e. floor(a/b).
Even an operator for modulo is rarely used at all. More common are
congruences
x === y === z (mod m)
where === denotes three horizontal lines. If modulo is used directly,
it's 'x mod y'.
--
__("< Marcin Kowalczyk * qrczak at knm.org.pl http://qrczak.ids.net.pl/
\__/
^^ SYGNATURA ZASTĘPCZA
QRCZAK
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